Open Discussion or Open Session or Open Space?

The words (Open Discussion/ Open Session/ Open Space) English literal meaning itself says it a lot but still sometimes people are confused about what they should use for a meet up. Whether it should be called open discussion or open session and where open space stands in. I am going to give it a try to explain it a bit.

Open Discussion:

Allowing people to put there opinion about the matter in a meeting makes it open for discussion. Usually the topics or agenda of such kind of meeting are already planned in advance.

Open Session:

Giving people freedom of attending/joining a meeting depending on their choice or priority is called the open session. The topic for the meeting is decided in advance but it gives the people freedom to change the discussion topic on common consensus. In a way, it implies that people have open discussion about the topic in open session.

Open Space:

Nothing is planned in advance. Everything is decided by the people on the go and like thinking people come together and go for organizing open session. In another way, you will have open sessions in open space.

So, how all this is related? In an open space you will be having open sessions and in open session you will be having open discussion, makes sense.